Comparator
Diff two documents structurally · worked in this tab, never sent anywhere
Original
Changed
Comparison
Paste a document into each side — or press Sample to try it with a pair that differs in a few interesting ways.
The work
Compare two JSON documents side by side and see what changed at a glance — red for what only the original has, green for what only the new one has, an arrow for every replaced value. Key order and formatting are ignored, so only real differences show up. Runs entirely in your browser.
This is a structural comparison, not a text diff. The two documents are parsed and then walked value by value, so reordered keys, different indentation and trailing whitespace never show up as changes — only differences that actually change what the JSON means.
Arrays are matched by identity where one exists (an id, key, uuid or name field), so inserting an element at the start reports one addition rather than rewriting every element after it. Elements that only changed position are reported as moves.
The result is drawn as one aligned document rather than a list: matching lines sit on the same row, red marks what exists only in the original, green what exists only in the changed document, and an arrow between them marks a value that was replaced. Runs of identical lines fold away, but the braces on the path down to each difference always stay on screen, so every change keeps the structure that locates it. Both documents are parsed and compared in a Web Worker inside this tab.